They were the Boy Scouts ________ to help elderly people cross the streets．
A.whose was the workB.to whom was the workC.it was whose workD.whose work it was在线课程D
解析：
该题考查定语从句的用法。定语从句中的it为形式主语，真正的主语为后面的不定式部分，故答案为D项。